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Analog Devices Inc. LT3950JMSE#PBF
- Part No.:
- LT3950JMSE#PBF
- Manufacturer:
- Analog Devices Inc.
- Category:
- LED Drivers
- Package:
- 16-TFSOP (0.118", 3.00mm Width) Exposed Pad
- Datasheet:
-
LT3950JMSE#PBF.pdf
- Description:
- IC LED DRV RGLTR PWM 1.5A 16MSOP
- Quantity:
- Payment:
- Shipping:
Inventory:1,512
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Product details
Overview
LT3950JMSE#PBF from Analog Devices is a 60V, 1.5A monolithic LED driver IC with integrated DMOS switch, supporting boost/SEPIC/buck/buck-boost topologies and delivering ±2% LED current regulation. It features internal exponential-scale PWM dimming (128:1 resolution), programmable 300kHz–2MHz switching frequency, and AEC-Q100 qualification for automotive lighting systems including headlamps and DRLs.
For engineers reviewing the LT3950JMSE#PBF datasheet, LT3950JMSE#PBF pinout, LT3950JMSE#PBF application, or LT3950JMSE#PBF equivalent, key selection criteria include its 16-lead MSOP package with exposed pad, dual regulation (CC/CV), fault reporting via open-drain FAULT pin, and support for both analog CTRL dimming and internal/external PWM dimming at up to 20,000:1 range.
Technical Context
The LT3950JMSE#PBF implements constant-current/constant-voltage control using a high-side current-sense amplifier (ISP/ISN) with 250mV full-scale threshold and an output voltage feedback loop referenced to 1.2V at FB. Its internal PWM generator maps linear voltage ramps on the PWM pin (0.2V–1.2V) to exponential duty ratio steps via 7-bit ADC quantization-preserving dimming resolution across 10%–100% range.
Switching is controlled by a fixed-frequency oscillator with RT-programmable frequency (300kHz–2MHz), spread spectrum modulation (25% depth), and external synchronization capability via SYNC/SPRD. Protection includes overcurrent (700mV ISP–ISN), open/short LED detection (FB-based thresholds), and thermal shutdown, all coordinated through integrated fault logic driving the open-drain FAULT pin.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Input Voltage Range | 3V to 60V - supports wide automotive battery transients (up to 48V transient) without external protection |
| Integrated Switch Rating | 1.5A, 60V DMOS - enables single-chip 10W LED drive in boost topology with minimal external components |
| LED Current Regulation Accuracy | ±2% - ensures consistent luminance across temperature and unit-to-unit variation in automotive lighting |
| Dimming Resolution | 128:1 internal exponential PWM + 20,000:1 external PWM - preserves perceptual linearity and avoids visible steps in low-brightness zones |
| Switching Frequency Range | 300kHz to 2MHz - allows trade-off between EMI filtering size (higher fSW) and efficiency (lower fSW) |
| Operating Junction Temperature | –40°C to +150°C - qualified per AEC-Q100 Grade 1, suitable for under-hood and headlamp module placement |
| Package | 16-lead MSOP with exposed pad - provides thermal path for >1W dissipation and compact layout in space-constrained modules |
Pinout & Package
LT3950JMSE#PBF is housed in a 16-lead plastic MSOP package with exposed thermal pad (Pin 17 = GND), θJA = 40°C/W. The exposed pad must be soldered to PCB ground for thermal and electrical integrity.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| ISP / ISN | High-side Kelvin current sense inputs | Measure LED string current with 250mV full-scale threshold; enable accurate CC regulation independent of ground noise |
| FB | Output voltage feedback input | Regulates output to 1.2V reference; triggers open/short LED fault when voltage deviates beyond 300mV or 1.3V thresholds |
| CTRL | Analog dimming control | Linearly scales LED current from 0% to 100% as voltage rises from 200mV to 1.2V - enables smooth analog dimming without PWM artifacts |
| PWM | Internal/external PWM dimming input | Accepts 0.2–1.2V analog signal for exponential dimming or digital 0–100% PWM signal for direct switching control |
| PWMTG | External PMOS gate driver | Drives high-side PMOS disconnect switch between VISP and VISP–7.5V - isolates LED string during off-cycles and fault conditions |
| SYNC/SPRD | Frequency sync & spread spectrum control | Tied to INTVCC for EMI reduction; driven by external clock for precise system-level timing alignment |
| FAULT | Open-drain fault indicator | Asserts low for open LED, short LED, overvoltage (FB >1.3V), or overcurrent (ISP–ISN >700mV) |
| EN/UVLO | Enable and input undervoltage lockout | Shuts down converter below 1.25V threshold with 32mV hysteresis - prevents erratic operation during cold-crank |
Key Features
| Feature | Design Value |
|---|---|
| AEC-Q100 Grade 1 qualification | Validated for automotive under-hood use (-40°C to +150°C junction), including HTOL, TC, and ESD testing per automotive standards |
| Dual regulation mode (CC/CV) | Prevents damage during open-LED faults by transitioning from constant-current to constant-voltage mode before overvoltage occurs |
| Exponential-scale internal PWM generator | Converts linear 0.2–1.2V ramp into logarithmic duty ratio steps - maintains 0.1% dimming resolution at 1% brightness and 0.4% at 10% |
| Programmable switching frequency | RT resistor sets fSW from 300kHz to 2MHz - enables optimization for EMI compliance (e.g., 2MHz avoids AM band) or efficiency (e.g., 500kHz) |
| Integrated fault reporting | Single open-drain FAULT pin signals four distinct failure modes (open/short LED, overvoltage, overcurrent) with dedicated voltage thresholds |
| PMOS gate driver with active clamp | PWMTG limits gate voltage to ≤7.5V below ISP - protects common 20V-rated PMOS switches used in automotive LED strings |
Applications
| Automotive Headlamps | Avionic Exterior Lighting |
|---|---|
Use Scenario: High-brightness LED arrays in adaptive driving beam (ADB) headlamps requiring precise current control and fast PWM dimming for dynamic light shaping. IC Role / Device Role / Timing Role: Constant-current LED driver with synchronized PWM dimming and fault-safe open-circuit protection. Use Value: Enables pixel-level dimming control while maintaining ±2% current accuracy across temperature, critical for ECE R149 and SAE J2999 compliance. |
Use Scenario: Wingtip position lights and anti-collision beacons in commercial aircraft, operating from 28V DC with strict EMI and reliability requirements. IC Role / Device Role / Timing Role: Multitopology LED driver supporting buck mode for 28V input, with spread-spectrum switching to meet DO-160 Section 21 Class A radiated emissions limits. Use Value: Eliminates need for external EMI filters due to integrated spread spectrum and robust 150°C operation in uncooled avionics bays. |
| Commercial Vehicle DRLs | Industrial Machine Vision Lighting |
Use Scenario: Daytime running lights in trucks and buses exposed to wide input voltage swings (9–32V) and ambient temperatures from –40°C to +85°C. IC Role / Device Role / Timing Role: Boost-mode LED driver with programmable UVLO hysteresis and AEC-Q100 qualification for harsh vehicle electrical environments. Use Value: Maintains stable 1.5A output during cold-crank (6.5V) and load-dump (38V) events without latch-off or component stress. |
Use Scenario: High-intensity strobed lighting for barcode scanners and automated optical inspection, requiring microsecond-level dimming response and repeatable pulse energy. IC Role / Device Role / Timing Role: Fast-settling CC driver with external PWM input and <50ns minimum on/off times for precise strobe timing control. Use Value: Delivers consistent LED pulse amplitude across 100Hz–10kHz strobe frequencies, enabling reliable image capture in high-speed production lines. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar LED driver applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| LT3965EMSE#PBF | 4-channel independent LED driver, 50mA/channel, I²C interface, no internal switch | Designed for RGBW color mixing and addressable lighting; lacks 60V/1.5A power stage | Select for multi-color or individually controlled LED arrays where programmability outweighs single-channel power density |
| TPS92692QPWPRQ1 | 65V, 2.5A automotive LED controller with external FETs; no integrated switch; analog/digital dimming | Requires external high-side NMOS and gate driver; higher peak current but larger BOM and layout area | Select when >1.5A output or discrete FET thermal management is required, accepting added complexity for scalability |
Compared with LT3950JMSE#PBF, LT3965EMSE#PBF trades integrated power density for channel count and digital control, while TPS92692QPWPRQ1 offers higher current headroom at the cost of external FETs and increased design effort - making LT3950JMSE#PBF optimal for compact, single-string automotive lighting where AEC-Q100, 1.5A capability, and exponential dimming are primary requirements.
Availability
LT3950JMSE#PBF is available at Aetrix Electronics and suitable for automotive lighting, avionic exterior lighting, and industrial machine vision applications requiring stable component supply, AEC-Q100 compliance, and long-term lifecycle support.
Supply support for LT3950JMSE#PBF includes scheduled delivery planning, volume procurement assistance, BOM continuity management, traceable sourcing, and lifecycle availability coordination for OEM customers, industrial embedded developers, connected-device designers, and electronics production programs.
Manufacturer
Analog Devices, Inc. is a global semiconductor company specializing in high-performance analog, mixed-signal, and digital signal processing technologies for precision instrumentation, industrial automation, and automotive systems.
The LT3950 product line delivers highly integrated, AEC-Q100-qualified LED drivers optimized for automotive front-lighting, DRLs, and signaling applications - emphasizing safety-critical fault reporting, wide input range, and high-resolution dimming in compact packages.
FAQ
What is the maximum LED string voltage supported by the LT3950JMSE#PBF?
The LT3950JMSE#PBF supports output voltages up to 60V, determined by its internal 60V DMOS switch rating and ISP pin absolute maximum rating. In boost configuration, this enables driving 15–17 white LEDs (3.4V each) or 8–10 red/amber LEDs (6.5V each) in series while maintaining margin for ripple and transients.
Does the LT3950JMSE#PBF require an external PMOS for PWM dimming?
No - the LT3950JMSE#PBF includes an integrated PWMTG pin that drives an external high-side PMOS switch for PWM dimming, but it does not include the PMOS itself. The PWMTG output actively clamps to VISP–7.5V (typ.) to safely drive standard 20V-gate-rated PMOS devices commonly used in automotive LED strings.
How does the LT3950JMSE#PBF handle open-LED fault conditions?
When an open-LED event occurs, the LT3950JMSE#PBF detects falling LED current below 10% of full scale while FB remains in regulation, then asserts the FAULT pin low and disables switching. Simultaneously, PWMTG goes high to disconnect the LED string, preventing overvoltage stress on output capacitors and downstream circuitry.
Can the LT3950JMSE#PBF operate in buck mode with a 12V input?
Yes - the LT3950JMSE#PBF supports buck, boost, SEPIC, and buck-boost topologies. In buck mode with 12V input, it regulates LED current by controlling duty cycle of the internal switch, with FB used for optional overvoltage protection. Output voltage must remain below VIN to maintain continuous conduction mode.
What is the purpose of the CTRL pin on the LT3950JMSE#PBF?
The CTRL pin on the LT3950JMSE#PBF provides analog dimming control: as voltage rises from 200mV to 1.2V, regulated LED current scales linearly from 0% to 100% of full scale. This enables flicker-free dimming without PWM frequency artifacts, ideal for interior lighting and camera-adjacent applications where EMI-sensitive sensors are present.
LT3950JMSE#PBF Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Analog Devices Inc.
- Series:
- -
- Package/Case:
- 16-TFSOP (0.118", 3.00mm Width) Exposed Pad
- Packaging:
- Tube
- Product Status:
- Active
- Type:
- DC DC Regulator
- Topology:
- SEPIC, Step-Down (Buck), Step-Up (Boost)
- Internal Switch(s):
- Yes
- Number of Outputs:
- 1
- Voltage - Supply (Min):
- 3V
- Voltage - Supply (Max):
- 60V
- Voltage - Output:
- 1.2V ~ 60V
- Current - Output / Channel:
- 1.5A
- Frequency:
- 300kHz ~ 2MHz
- Dimming:
- PWM
- Applications:
- Backlight
- Operating Temperature:
- -40°C ~ 150°C (TA)
- Grade:
- Automotive
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 16-MSOP-EP
LT3950JMSE#PBF FAQ
1.How can I place an order for LT3950JMSE#PBF through Aetrix?
Please submit a Request for Quotation (RFQ) for LT3950JMSE#PBF on Aetrix. Our sales agent will provide a competitive quotation and guide you through the order confirmation once you accept the terms.
2.Are the price and stock information for LT3950JMSE#PBF reliable?
The price and inventory of LT3950JMSE#PBF are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LT3950JMSE#PBF is usually 5 days.
3.What payment methods are accepted for LT3950JMSE#PBF?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LT3950JMSE#PBF transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LT3950JMSE#PBF?
LT3950JMSE#PBF orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LT3950JMSE#PBF order is processed, you will receive an email with the shipment details and tracking number.
Note: Tracking information may take up to 24 hours to appear. Express delivery typically takes 3–5 business days.
5.How can I obtain technical support or documentation for LT3950JMSE#PBF?
For technical support, including LT3950JMSE#PBF datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LT3950JMSE#PBF requirements.
6.How does Aetrix verify that LT3950JMSE#PBF is sourced from the original manufacturer or authorized distributors?
All LT3950JMSE#PBF products on Aetrix are procured from qualified distributors and authorized channels. Our dedicated quality assurance team conducts strict verification, including traceability checks and, if necessary, third-party testing. This ensures that LT3950JMSE#PBF meets industry standards.
7.What is the process for return or replacement of LT3950JMSE#PBF?
All LT3950JMSE#PBF units undergo pre-shipment inspection (PSI). If there is an issue with LT3950JMSE#PBF, returns or replacements are accepted under the following conditions:
1.Quantity discrepancies, incorrect items, or visible external defects (such as breakage or corrosion), acknowledged by Aetrix.
2.The issue is reported within 90 days of delivery.
3.The LT3950JMSE#PBF part is unused and in its original packaging.
Return procedure for LT3950JMSE#PBF:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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